/*
 * Cobertura - http://cobertura.sourceforge.net/
 *
 * Copyright (C) 2005 Jeremy Thomerson
 * Copyright (C) 2005 Grzegorz Lukasik
 *
 * Cobertura is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published
 * by the Free Software Foundation; either version 2 of the License,
 * or (at your option) any later version.
 *
 * Cobertura is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with Cobertura; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
 * USA
 */
package net.sourceforge.cobertura.util;

import java.io.File;
import java.io.IOException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Set;

import org.apache.log4j.Logger;


/**
 * Maps source file names to existing files. After adding description
 * of places files can be found in, it can be used to localize 
 * the files. 
 * 
 * <p>
 * FileFinder supports two types of source files locations:
 * <ul>
 *     <li>source root directory, defines the directory under 
 *     which source files are located,</li>
 *     <li>pair (base directory, file path relative to base directory).</li>
 * </ul>
 * The difference between these two is that in case of the first you add all
 * source files under the specified root directory, and in the second you add
 * exactly one file. In both cases file to be found has to be located under 
 * subdirectory that maps to package definition provided with the source file name.      
 *  
 * @author Jeremy Thomerson
 */
public class FileFinder {

	private static Logger LOGGER = Logger.getLogger(FileFinder.class);
	
	// Contains Strings with directory paths
	private Set sourceDirectories = new HashSet();
	
	// Contains pairs (String directoryRoot, Set fileNamesRelativeToRoot)
	private Map sourceFilesMap = new HashMap();

	/**
	 * Adds directory that is a root of sources. A source file
	 * that is under this directory will be found if relative
	 * path to the file from root matches package name.
	 * <p>
	 * Example:
	 * <pre>
	 * fileFinder.addSourceDirectory( "C:/MyProject/src/main");
	 * fileFinder.addSourceDirectory( "C:/MyProject/src/test");
	 * </pre>
	 * In path both / and \ can be used.
	 * </p> 
	 * 
	 * @param directory The root of source files 
	 * @throws NullPointerException if <code>directory</code> is <code>null</code>
	 */
	public void addSourceDirectory( String directory) {
		if( LOGGER.isDebugEnabled())
			LOGGER.debug( "Adding sourceDirectory=[" + directory + "]");

		// Change \ to / in case of Windows users
		directory = getCorrectedPath(directory);
		sourceDirectories.add(directory);
	}

	/**
	 * Adds file by specifying root directory and relative path to the
	 * file in it. Adds exactly one file, relative path should match
	 * package that the source file is in, otherwise it will be not
	 * found later.
	 * <p>
	 * Example:
	 * <pre>
	 * fileFinder.addSourceFile( "C:/MyProject/src/main", "com/app/MyClass.java");
	 * fileFinder.addSourceFile( "C:/MyProject/src/test", "com/app/MyClassTest.java");
	 * </pre>
	 * In paths both / and \ can be used.
	 * </p>
	 * 
	 * @param baseDir sources root directory
	 * @param file path to source file relative to <code>baseDir</code>
	 * @throws NullPointerException if either <code>baseDir</code> or <code>file</code> is <code>null</code>
	 */
	public void addSourceFile( String baseDir, String file) {
		if( LOGGER.isDebugEnabled())
			LOGGER.debug( "Adding sourceFile baseDir=[" + baseDir + "] file=[" + file + "]");

		if( baseDir==null || file==null)
			throw new NullPointerException();
	
		// Change \ to / in case of Windows users
		file = getCorrectedPath( file);
		baseDir = getCorrectedPath( baseDir);
		
		// Add file to sourceFilesMap
		Set container = (Set) sourceFilesMap.get(baseDir);
		if( container==null) {
			container = new HashSet();
			sourceFilesMap.put( baseDir, container);
		}
		container.add( file);
	}

	/**
	 * Maps source file name to existing file.
	 * When mapping file name first values that were added with
	 * {@link #addSourceDirectory} and later added with {@link #addSourceFile} are checked.
	 * 
	 * @param fileName source file to be mapped
	 * @return existing file that maps to passed sourceFile 
	 * @throws IOException if cannot map source file to existing file
	 * @throws NullPointerException if fileName is null
	 */
	public File getFileForSource(String fileName) throws IOException {
		// Correct file name
		if( LOGGER.isDebugEnabled())
			LOGGER.debug( "Searching for file, name=[" + fileName + "]");
		fileName = getCorrectedPath( fileName);

		// Check inside sourceDirectories
		for( Iterator it=sourceDirectories.iterator(); it.hasNext();) {
			String directory = (String)it.next();
			File file = new File( directory, fileName);
			if( file.isFile()) {
				LOGGER.debug( "Found inside sourceDirectories");
				return file;
			}
		}
		
		// Check inside sourceFilesMap
		for( Iterator it=sourceFilesMap.keySet().iterator(); it.hasNext();) {
			String directory = (String)it.next();
			Set container = (Set) sourceFilesMap.get(directory);
			if( !container.contains( fileName))
				continue;
			File file = new File( directory, fileName);
			if( file.isFile()) {
				LOGGER.debug( "Found inside sourceFilesMap");
				return file;
			}
		}

		// Have not found? Throw an error.
		LOGGER.debug( "File not found");
		throw new IOException( "Cannot find source file, name=["+fileName+"]");
	}

	/**
	 * Returns a list with string for all source directories.
	 * Example: <code>[C:/MyProject/src/main,C:/MyProject/src/test]</code>
	 * 
	 * @return list with Strings for all source roots, or empty list if no source roots were specified 
	 */
	public List getSourceDirectoryList() {
		// Get names from sourceDirectories
		List result = new ArrayList();
		for( Iterator it=sourceDirectories.iterator(); it.hasNext();) {
			result.add( it.next());
		}
		
		// Get names from sourceFilesMap
		for( Iterator it=sourceFilesMap.keySet().iterator(); it.hasNext();) {
			result.add(it.next());
		}
		
		// Return combined names
		return result;
	}

    private String getCorrectedPath(String path) {
        return path.replace('\\', '/');
    }

    /**
     * Returns string representation of FileFinder.
     */
    public String toString() {
    	return "FileFinder, source directories: " + getSourceDirectoryList().toString();
    }
}
